tech2 News StaffAug 30, 2019 19:03:22 IST
Chandrayaan 2, India's second mission to the moon, has successfully compeleted its fourth orbit-lowering manoeuvre around the moon. ISRO confirmed that the lunar-bound manoeuvre, which was planned for 6-7 am on 30 August, was completed at 6.18 pm IST using the spacecraft's onboard propulsion system.
The manoeuvre has moved Chandrayaan 2 from its current 179 x 1411 km (nearest x farthest distance) elliptical orbit to a near-circular orbit of 124 x 164 km and the duration of the manoeuvre was 1155 seconds (19.25 minutes). The next Lunar bound orbit manoeuvre is scheduled on September 01, 2019 between 6.00 pm - 7.00 pm IST.
The Chandrayaan 2 composite has carried out a total of four successful in-orbit manoeuvres since it entered lunar orbit — all in an attempt to lower its altitude in preparation for landing. The fourth manoeuvre today has placed the spacecraft on a circular path that passes over the lunar poles at a distance of about 100 km from the surface.
Entering this circular orbit is the mission's fourth milestone before the Vikram lander separates from the orbiter to make its planned soft-landing on the moon's surface on 7 September.
The 124 x 164 km circular orbit that Chandrayaan 2 is in is close enough for the Vikram lander, currently bound to the orbiter in a 'composite', to separate and attempt a landing. Separation and landing sequences are planned for 2 September and 7 September at 1.40 am, respectively. Between these two important days, the first maps of the landing site will be created (on 3 and 4 September) to ensure the landing site is as safe as previously thought to make a soft-landing. This is a crucial step in the mission since ISRO's mission engineers won't be operating the spacecraft remotely.
The orbiter will also be surveilling its year-long home for the first time, ensuring that no damage was caused to its instruments on the journey thus far, and conducting a thorough examination of the Vikram lander's landing site at the moon's South Polar region. Chandrayaan 2 is expected to begin its long-awaited powered descent and landing on 7 September at 1.40 am IST in a landing sequence that the ISRO Chief describes as '15 minutes of terror'.